Adsorption of U(Ⅵ) Onto Nano-Fe3O4 Coated by Polyvinyl Pyrrolidone

Abstract

The nano-Fe3O4 coated by polyvinyl pyrrolidone was systematically conducted this research as U(Ⅵ) adsorbent about the effect of pH value, initial U(Ⅵ) concentration, temperature, ion strength and adsorption time on U(Ⅵ) adsorption, meanwhile study the adsorption isotherm models, kinetics, thermodynamics and adsorption recycles. Results show that the adsorption equilibrium time is from 5 to 60 minutes when the pH value is 6.00 at 20-40 ℃, and the removal rate of U(Ⅵ) is more than 75%. The kinetic of U(Ⅵ) adsorption onto Fe3O4@PVP is nearly to pseudo-secondary adsorption kinetics and obeys Redlich-Peterson and Langmuir models. The adsorption rate constant of U(Ⅵ) adsorption onto Fe3O4@PVP is 0.000 646-0.012 500 g/(mg·min) at 20-40 ℃, and the corresponding maximum adsorption capacity of Langmuir isotherm models is 185.8-291.0 mg/g. Thermodynamic studies reveal that the adsorption process of U(Ⅵ) onto Fe3O4@PVP is endothermic and spontaneous（ΔH＞0, ΔG＜0）.

Keywords

• pvp-coated
• nano-fe3o4
• u(ⅵ) adsorption
• adsorption kinetics
• magnetic separation